┌─────────────────────────────────────────────────────────────┐
│                    Quality Recticel Web App                 │
│                  (print_module.html)                       │
└─────────────────────┬───────────────────────────────────────┘
                      │ HTTP Request
                      ▼
┌─────────────────────────────────────────────────────────────┐
│              Windows Print Service                          │
│                (localhost:8765)                            │
│  ┌─────────────┐  ┌──────────────┐  ┌─────────────────┐   │
│  │   Flask     │  │    CORS      │  │   PDF Handler   │   │
│  │   Server    │  │   Support    │  │                 │   │
│  └─────────────┘  └──────────────┘  └─────────────────┘   │
└─────────────────────┬───────────────────────────────────────┘
                      │ Native Messaging
                      ▼
┌─────────────────────────────────────────────────────────────┐
│                Chrome Extension                             │
│  ┌─────────────┐  ┌──────────────┐  ┌─────────────────┐   │
│  │ Background  │  │  Content     │  │     Popup       │   │
│  │ Service     │  │  Script      │  │     UI          │   │
│  │ Worker      │  │              │  │                 │   │
│  └─────────────┘  └──────────────┘  └─────────────────┘   │
└─────────────────────┬───────────────────────────────────────┘
                      │ Windows API
                      ▼
┌─────────────────────────────────────────────────────────────┐
│                Windows Print System                         │
└─────────────────────────────────────────────────────────────┘

📁 Project Structure

windows_print_service/
├── 📄 print_service.py           # Main Flask service
├── 📄 service_manager.py         # Windows service wrapper  
├── 📄 install_service.bat        # Installation script
├── 📄 INSTALLATION_GUIDE.md      # Complete documentation
├── 📄 QUICK_SETUP.md            # User quick reference  
├── 📄 README.md                 # This file
└── 📁 chrome_extension/         # Chrome extension
    ├── 📄 manifest.json         # Extension manifest v3
    ├── 📄 background.js         # Service worker
    ├── 📄 content.js           # Page content integration
    ├── 📄 popup.html           # Extension popup UI
    ├── 📄 popup.js            # Popup functionality
    └── 📁 icons/              # Extension icons

🚀 API Endpoints

Base URL: `http://localhost:8765`

Endpoint	Method	Description	Request Body	Response
`/health`	GET	Service health check	None	`{"status": "healthy", ...}`
`/printers`	GET	List available printers	None	`{"printers": [...]}`
`/print/pdf`	POST	Print PDF from URL	`{"url": "...", "printer": "..."}`	`{"success": true, ...}`
`/print/silent`	POST	Silent print with metadata	`{"pdf_url": "...", "order_id": "..."}`	`{"success": true, ...}`

Example API Usage

// Health Check
const health = await fetch('http://localhost:8765/health');
const status = await health.json();

// Silent Print
const printRequest = {
    pdf_url: 'http://localhost:5000/generate_labels_pdf/123',
    printer_name: 'default',
    copies: 1,
    silent: true,
    order_id: '123',
    quantity: '10'
};

const response = await fetch('http://localhost:8765/print/silent', {
    method: 'POST',
    headers: {'Content-Type': 'application/json'},
    body: JSON.stringify(printRequest)
});

🔧 Development Setup

Prerequisites

Python 3.8+
Windows 10/11
Chrome Browser
Administrator privileges

Local Development

# Clone/download the project
cd windows_print_service

# Install dependencies
pip install flask flask-cors requests pywin32

# Run development server (not as service)
python print_service.py

# Install as Windows service
python service_manager.py install

# Service management
python service_manager.py start
python service_manager.py stop  
python service_manager.py restart
python service_manager.py uninstall

Chrome Extension Development

# Load extension in Chrome
chrome://extensions/ → Developer mode ON → Load unpacked

# Debug extension
chrome://extensions/ → Details → Background page (for service worker)
chrome://extensions/ → Details → Inspect views (for popup)

📋 Configuration

Service Configuration (`print_service.py`)

class WindowsPrintService:
    def __init__(self, host='127.0.0.1', port=8765):
        self.host = host      # Localhost binding only
        self.port = port      # Service port
        self.app = Flask(__name__)

Chrome Extension Permissions (`manifest.json`)

{
    "permissions": [
        "printing",           // Access to printer API
        "nativeMessaging",   // Communication with Windows service
        "activeTab",         // Current tab access
        "storage"           // Extension settings storage
    ]
}

🔄 Integration Flow

1. Service Detection

// Web page detects service availability
const isServiceAvailable = await checkServiceHealth();
updatePrintButton(isServiceAvailable);

2. Print Request Flow

User clicks print → Web app → Windows service → Chrome extension → Printer

3. Fallback Mechanism

Service unavailable → Fallback to PDF download → Manual printing

🛠️ Customization

Adding New Print Options

# In print_service.py
@app.route('/print/custom', methods=['POST'])
def print_custom():
    data = request.json
    # Custom print logic here
    return jsonify({'success': True})

Modifying Chrome Extension

// In background.js - Add new message handler
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
    if (message.type === 'CUSTOM_PRINT') {
        // Custom print logic
    }
});

Web Application Integration

// In print_module.html - Modify print function
async function customPrintFunction(orderId) {
    const response = await fetch('http://localhost:8765/print/custom', {
        method: 'POST',
        body: JSON.stringify({orderId, customOptions: {...}})
    });
}

🧪 Testing

Unit Tests (Future Enhancement)

# test_print_service.py
import unittest
from print_service import WindowsPrintService

class TestPrintService(unittest.TestCase):
    def test_health_endpoint(self):
        # Test implementation
        pass

Manual Testing Checklist

Service starts automatically on Windows boot
API endpoints respond correctly
Chrome extension loads without errors
Print jobs execute successfully
Fallback works when service unavailable
Firewall allows port 8765 traffic

📊 Monitoring & Logging

Log Files

Service Log: print_service.log (Flask application logs)
Windows Event Log: Windows Services logs
Chrome DevTools: Extension console logs

Health Monitoring

# Monitor service health
import requests
try:
    response = requests.get('http://localhost:8765/health', timeout=5)
    if response.status_code == 200:
        print("✅ Service healthy")
except:
    print("❌ Service unavailable")

🔒 Security Considerations

Network Security

Localhost Only: Service binds to 127.0.0.1 (no external access)
No Authentication: Relies on local machine security
Firewall Rule: Port 8765 opened for local connections only

Chrome Extension Security

Manifest V3: Latest security standards
Minimal Permissions: Only necessary permissions requested
Sandboxed: Runs in Chrome's security sandbox

Windows Service Security

System Service: Runs with appropriate Windows service privileges
Print Permissions: Requires printer access (normal for print services)

🚀 Deployment

Production Deployment

Package Distribution:

# Create deployment package
zip -r quality_recticel_print_service.zip windows_print_service/

Installation Script: Use install_service.bat for end users
Group Policy Deployment: Deploy Chrome extension via enterprise policies

Enterprise Considerations

Silent Installation: Modify install_service.bat for unattended install
Registry Deployment: Pre-configure Chrome extension registry entries
Network Policies: Ensure firewall policies allow localhost:8765

📚 Dependencies

Python Packages

flask>=2.3.0          # Web framework
flask-cors>=4.0.0     # CORS support
requests>=2.31.0      # HTTP client
pywin32>=306          # Windows service integration

Chrome APIs

chrome.printing.* - Printing functionality
chrome.runtime.* - Extension messaging
chrome.nativeMessaging.* - Native app communication

🐛 Debugging

Common Debug Commands

# Check service status
sc query QualityRecticelPrintService

# Test API manually  
curl http://localhost:8765/health

# Check listening ports
netstat -an | findstr :8765

# View service logs
type print_service.log

Chrome Extension Debugging

// In background.js - Add debug logging
console.log('Print request received:', message);

// In popup.js - Test API connection
fetch('http://localhost:8765/health')
    .then(r => r.json())
    .then(data => console.log('Service status:', data));

📄 License & Support

Project: Quality Recticel Print Service
Version: 1.0
Compatibility: Windows 10/11, Chrome 88+
Maintenance: Zero-maintenance after installation

For technical support, refer to INSTALLATION_GUIDE.md troubleshooting section.

README.md

Quality Recticel Windows Print Service

🏗️ Technical Architecture